HEAT EXCHANGER OF THE DESK TYPE

Abstract: For applications operating at high temperatures and pressures there is designed a heat exchanger comprising a core (1) made of plan parallely and mutually in distance arranged plates (7), defining passages for heat exchanging fluids, the core (1) being compressed between end panels (2) by tie rods. The heat exchanger further comprises a spacer (10) filled with insulation (12) and arranged between the core (1) and each of the end panels (2). The end panels (2) are sprung away from the core (1) by resilient elements located between the end panels (2) and the spacers (10) and/or located on the tie rods (3).

Description: HEAT EXCHANGER OF THE DESK TYPE Technical Field The invention relates to a heat exchanger of the desk type, having a core made of planparallelly and mutually in distance arranged plates, defining passages for heat exchanging fluids, the core being compressed between end panels by means of tie rods. Background of the Invention Heat exchangers of the known construction have a core consisting of plates compressed between rigid end panels by means of tie rods fixing their position and a rigidity of the whole assembly. Individual adjacent plates are mutually separated by spacing elements of various shapes, the elements defining pluralities of parallelly arranged channels for which it applies that channels in one layer are perpendicular to the channels in adjoining layers. Such embodiments with end panels in direct contact with the plate core are satisfactory for low temperature applications showing only low level of • friction between the end panels and the core due to the low differential thermal expansion. Therefore the plates retain their structural rigidity and strength. Systems operating at high pressure and temperature manifest much complicated service conditions providing for a couple of problems. Due to the high temperature the panels loose their strength, particularly when they are covered by insulation allowing for reduction of heat losses and protection of personnel working in close vicinity. Under these conditions the difference of the thermal expansion of the end plate and the core respectively is large and results in an intense friction and fretting which very often damage the core- Disclosure and Object of the Invention The foregoing problems are solved by a heat exchanger of the desk type, having a core made of planparallelly and mutually in distance arranged plates, defining passages for heat exchanging fluids, the core being compressed between end panels by means of tie rods in an embodiment in accordance with the present invention comprising spacers filled with insulation, the spacer being arranged between the core and each of the end panels. Further in accordance with the present invention the end panels are sprung away from the core, advantageously by means of elastic elements located between the end panels and the spacers and/or located on the tie rods. Still further in accordance with the invention the spacer comprises a plurality of crossbars and in a preferred embodiment the the spacer is of a honeycomb construction. It is an object of the invention to create thermal isolation layers protecting end panels from excessive heat from the core thus decreasing the panel temperature to the level only very little above the ambient temperature. The spacer further provides for uniform distribution of the temperature gradient between the core and the end panel. It results in negligible temperature difference between- the spacer and the adjoining core plate and the end plate respectively, which practically eliminates friction and fretting at contact surfaces of these parts. It is a further object of the invention to achieve a uniform distribution of compressiwe forces applied upon the core by the end panels which results in lower mechanical stress of tie rods and the core as well. Brief Description of the Drawings By way of examples the invention will be now described with reference to the accompanying drawing- Fig- 1 illustrates completely assembled heat exchanger. while Fig. 2 shows the same in partially dismantled setup, Fig- 3 presents particular parts of the heat exchanger and Fig. 4 offers details of the core according to the Fig. 3- Description of Preferred Embodiments Referring to Fig- 3, the heat exchanger according to the invention, similarly to those already existing ones, comprises plate core 1, which is compressed between two end panels 2 by means of tie rods. In this embodiment the tie rods are provided for by bolts 3 passing through sleeves 4 which are distributed along end panel 2 edges. The position of end plates 2 and pressure applied by them upon the core 1 are secured by nuts 5- Each end panel 2 is on its outside surface provided with crossbars 6- The core 1 consists of flat plates 7, arranged in a planparallel layout and mutually separated by spacing elements 8 being set apart at regular intervals. The spacing elements 8 define intermediate space between adjoining plates 7, thus allowing for flow of heat-exchanging fluids and preventing excessive mechanical stress and the plate 7 deformation. The edge bars 9 located along the plate 7 edges are well sealed against the adjoining plates 7, advantageously by welds, thus providing for enclosure of the inner core 1 space. Distribution heads 14 provide for particular inlets and outlets of heat-exchanging fluids into and out of the intermediate spaces of the core 1 plates 7. Such solution constituting prior art of the problems in question, is according to the invention provided with spacers IO, which are of a honeycomb construction. The said spacers IO are placed between the core 1 and respective end plates 2. Space between spacing bars 11 of the spacers IO is filled with thermal insulation 12- The spacers IO allow for uniform distribution of pressure forces applied upon the core 1 by the end panels 2 and for uniform distribution of a thermal gradient showing maximum values at the core 1 surface and minimum val es at the outer surface of the end panels 2. The temperature of the spacers IO and the core 1 in their contact area is nearly the same for both elements and their thermal expansion being virtually equal is thus accompanied by very little or no friction. This applies similarly for the spacers IO and the end panels 2. Uniform temperature gradient existing across the spacer IO provides for low thermal and mechanical stress not only of these parts but also of adjoining core 1 and the end plate 2. Stress due to different thermal expansion of the core and the bolts 3 is accommodated by springs 13 which simultaneously apply sufficient compressive force upon the core 1 under any operational conditions. The core 1 can be sprung away from the end panels 2 also by resilient elements placed between the end panels 2 and the spacer IO- Bolts 3 or any similar tying rods can be attached to end panels 2 also by means of welding. Industrial applications The present invention is designed for any application of heat exchangers operating at high temperatures and pressures-

Claims: C L I M S 1. Heat exchanger of the desk type, having a core made of planparallelly and mutually in distance arranged plates, defining passages for heat exchanging fluids, the core being compressed between end panels by means of tie rods, characterized in, between the core (1) and each of the end panels (2) there is arranged a spacer (10) filled with insulation (12). 2. Heat exchanger according the claim 1, characterized in, that the end panels (2) are sprung away from the core (1) . 3. Heat exchanger according the claim 2, characterized in, that resilient elements are located between the end panels (2) and the spacers (10) and/or located on the tie rods (3). 4. Heat exchanger according the claim 1, characterized in, that the spacer (10) comprises a plurality of crossbars (11). 5. Heat exchanger according the claim 1, characterized in, that the spacer (10) is of a honeycomb construction.

Inventors: DINULESCU MIRCEA, DINULESCU, MIRCEA
Applicants: DINULESCU MIRCEA, DINULESCU, MIRCEA
Application year: 1994
Main classification: F28F3
IPC codes: F28D9, F28F3